Removed the 7900GS, Installed the latest drivers for Nvidia 196.21 and installed DVI to VGA adaptor in second card and all is well! Panic over, have noticed though that grpahics are a bit jumpy, but ever time i whack the 7900gs it cocks up not only the drivers but boinc wont connect to locahost either! So its staying out!

the 7900 wont run Seti so its useless for seti. You're better off plugging your monitor into one of the other cards and dealing with your video from them. The video from them shouldn't be bad since those cards should have ample RAM to run your desktop and CUDA tasks
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In a rich man's house there is no place to spit but his face.
Diogenes Of Sinope